A concurrent error detection based fault-tolerant 32 nm XOR-XNOR circuit implementation

As modern processors and semiconductor circuits move into 32 nm technologies and below, designers face the major problem of process variations. This problem makes designing VLSI circuits harder and harder, affects the circuit performance and introduces faults that can cause critical failures. Therefore, fault-tolerant design is required to obtain the necessary level of reliability and availability especially for safety-critical systems. Since XOR-XNOR circuits are basic building blocks in various digital and mixed systems, especially in arithmetic circuits, these gates should be designed such that they indicate any malfunction during normal operation. In fact, this property of verifying the results delivered by a circuit during its normal operation is called Concurrent Error Detection (CED). In this paper, we propose a CED based fault- tolerant XOR-XNOR circuit implementation. The proposed design is performed using the 32 nm process technology.published_or_final_versio

Influence of Doping and Nanostructuration on n-Type Bi2(Te0.8Se0.2)3 Alloys Synthesized by Arc Melting

In competitive thermoelectric devices for energy conversion and generation, high-efficiency materials of both n-type and p-type are required. For this, Bi2Te3-based alloys have the best thermoelectric properties in room temperature applications. Partial replacement of tellurium by selenium is expected to introduce new donor states in the band gap, which would alter electrical conductivity and thermopower. We report on the preparation of n-type Bi2(Te1-xSex)3 solid solutions by a straightforward arc-melting technique, yielding nanostructured polycrystalline pellets. X-ray and neutron powder diffraction was used to assess Se inclusion, also indicating that the interactions between quintuple layers constituting this material are weakened upon Se doping, while the covalency of intralayer bonds is augmented. Moreover, scanning electron microscopy shows large surfaces perpendicular to the c crystallographic axis assembled as stacked sheets. Grain boundaries related to this 2D nanostructuration affect the thermal conductivity reducing it below 0.8 Wm−1K−1 at room temperature. Furthermore, Se doping increases the absolute Seebeck coefficient up to −140 μV K−1 at 400 K, which is also beneficial for improved thermoelectric efficiency.This research was funded by the Spanish Ministry of Economy and Competitivity for granting the project MAT2013-41099-R.Peer reviewe

Nanostructured Thermoelectric Chalcogenides

Thermoelectric materials are outstanding to transform temperature differences directly and reversibly into electrical voltage. Exploiting waste heat recovery as a source of power generation could help towards energy sustainability. Recently, the SnSe semiconductor was identified, in single-crystal form, as a mid-temperature thermoelectric material with record high figure of merit, high power factor and surprisingly low thermal conductivity. We describe the preparation of polycrystals of alloys of SnSe obtained by arc-melting; a rapid synthesis that results in strongly nanostructured samples with low thermal conductivity, advantageous for thermoelectricity, approaching the amorphous limit, around 0.3–0.5 W/mK. An initial screening of novel samples Sn1−xMxSe, by alloying with 3d and 4d transition metals such as M = Mn, Y, Ag, Mo, Cd or Au, provides for a means to optimize the power factor. M=Mo, Ag, with excellent values, are described in detail with characterization by x-ray powder diffraction (XRD), scanning electron microscopy (SEM), and electronic and thermal transport measurements. Rietveld analysis of XRD data demonstrates near-perfect stoichiometries of the above-mentioned alloys. SEM analysis shows stacking of nanosized sheets, with large surfaces parallel to layered slabs. An apparatus was developed for the simultaneous measurement of the Seebeck coefficient and electric conductivity at elevated temperatures

Silver Nanoparticles in the Cultural Heritage Conservation

Our cultural heritage is our invaluable social and environmental resource and concern. Moreover, it is a key global economic driver. However, they are subjected to deterioration process and aging. Particularly, microorganisms are nowadays considered harmful agents of biodeterioration of artistic materials due to the fact that their interactions with the material cause not only an esthetical damage due to their visible growth on the surface, but they may affect the interested materials in different ways and at different degrees via mechanical and biochemical processes leading to the formation of pitting, scaling and, in the worst scenario, to the loss of material by its detachment. To protect our shared tangible cultural heritage from biodeterioration and preserve it for future generations, several methods have been developed. Notably, using nanomaterials, with antimicrobial features, has been considered an interesting and economical method to preserve valuable heritage materials. In this chapter, we will present an overview of the decay mechanisms that participate in the deterioration of tangible artworks, in particular microorganisms’ colonization. Next, current works that have been developed to use silver nanoparticles to protect heritage items from microbial colonization and prevent their deterioration have been detailed

Nanostructured State-of-the-Art Thermoelectric Materials Prepared by Straight-Forward Arc-Melting Method

Thermoelectric materials constitute an alternative to harvest sustainable energy from waste heat. Among the most commonly utilized thermoelectric materials, we can mention Bi2Te3 (hole and electron conductivity type), PbTe and recently reported SnSe intermetallic alloys. We review recent results showing that all of them can be readily prepared in nanostructured form by arc-melting synthesis, yielding mechanically robust pellets of highly oriented polycrystals. These materials have been characterized by neutron powder diffraction (NPD), scanning electron microscopy (SEM) and electronic and thermal transport measurements. Analysis of NPD patterns demonstrates near-perfect stoichiometry of above-mentioned alloys and fair amount of anharmonicity of chemical bonds. SEM analysis shows stacking of nanosized sheets, each of them presumably single-crystalline, with large surfaces parallel to layered slabs. This nanostructuration affects notably thermoelectric properties, involving many surface boundaries (interfaces), which are responsible for large phonon scattering factors, yielding low thermal conductivity. Additionally, we describe homemade apparatus developed for the simultaneous measurement of Seebeck coefficient and electric conductivity at elevated temperatures

Gastrointestinal lesions in patients with acquired immunodeficiency syndrome

"Introduction : Le syndrome de l'immunodéficience acquise (SIDA) s'accompagne souvent d'atteintes du tube digestif, tumorales ou secondaires à des infections opportunistes. Le but du travail est de déterminer les aspects endoscopiques et anatomo-pathologiques des atteintes digestives secondaires au SIDA et d'étudier leur corrélation. Patients et méthodes : 68 patients atteints du SIDA ont été explorés au service EFD-HGE sur une période de 5 ans. Tous les patients ont bénéficié d'une endoscopie œso-gastro-duodénale (EOGD) et/ou d'une iléo-coloscopie avec une étude anatomo-pathologique des biopsies. Résultats : Les lésions digestives hautes étaient: une œsophagite mycosique dans 19 cas, une gastrite congestive dans 14 cas, une gastrite ulcérative chez un patient, une gastrite érosive chez un patient, une duodénite congestive dans 9 cas et des lésions angiomateuses très évocatrices de la maladie de Kaposi dans 6 cas. L'étude anatomo-pathologique des biopsies a conclu à des lésions digestives hautes liées au SIDA dans 27 cas (53 %). Les lésions digestives basses étaient : une colite ulcérative dans 22 cas, des angiodysplasies dans 4 cas, une colite érosive dans 16 cas. La coloscopie totale était normale chez 2 patients. L'étude anatomo-pathologique des biopsies iléales et coliques a conclu à des lésions secondaires au SIDA dans 8 cas (18,1 %). Il existait une corrélation statiquement significative entre les aspects endoscopiques et anatomopathologiques spécifiques au SIDA (coefficient kappa = 0,730). Conclusion : Les atteintes digestives liées au SIDA sont assez fréquentes, elles étaient de 51,4 % dans cette étude dominées par les infections opportunistes. Une corrélation était retrouvée entre les lésions endoscopiques et spécifiques au SIDA.Background: The acquired immunodeficiency syndrome (AIDS) is often associated of the gastrointestinal lesions, tumor or secondary to opportunistic infections. The aim of this study is to determine the endoscopic and histopathological gastrointestinal lesions of AIDS and study their correlation. Patients and Method: 68 patients with AIDS were explored in our unit over a five-year period. All patients underwent an upper gastrointestinal endoscopy and/or a total colonoscopy with histopathological study of biopsies. The kappa coefficient was used to calculate the correlation between endoscopic and histopathological lesions specific to AIDS. Results: Upper gastrointestinal endoscopy revealed: fungal esophagitis in 19 cases, congestive gastritis in 14 cases, ulcerative gastritis in a patient, erosive gastritis in a patient, congestive duodenitis in 9 cases, and angiomatous lesions of Kaposi's sarcoma in 6 cases. Histopathological study of biopsies concluded to specific upper gastrointestinal lesions of AIDS in 27 cases (54%): Candida albicans in 19 patients, Kaposi's sarcoma in 6 cases, Cytomegalovirus (CMV) gastritis in 1 case, gastric cryptosporidiosis associated with Cytomegalovirus gastritis in 1 case. Colonoscopy objectified: ulcerative colitis in 22 cases, 4 cases of angiodysplasia, erosive colitis in 16 cases. Histopathological study of ileal and colonic biopsies concluded to specific lesions of AIDS in 8 cases (18.1%). Significant correlation was found between endoscopic and histopathological lesions specific of AIDS (kappa = 0.730). Conclusion: Gastrointestinal lesions specific of AIDS are fairly common, they were 52.2% in this study dominated by opportunistic infections. A correlation was found between endoscopic and histopathological lesions specific of AIDS in this study

Behavioural thermoregulation via microhabitat selection of winter sleeping areas in an endangered primate: implications for habitat conservation

Strategic microhabitat selection allows animals in seasonally cold environments to reduce homeostatic energy costs, particularly overnight when thermoregulatory demands are greatest. Suitable sleeping areas may therefore represent important resources for winter survival. Knowledge of microhabitat use and potential impacts of anthropogenic habitat modification can aid species conservation through development of targeted habitat management plans. Wild, endangered Barbary macaques (Macaca sylvanus) in logged cedar-oak forest were studied to investigate (1) the hypothesis that macaques select winter sleeping areas with microhabitat characteristics that may reduce thermoregulatory costs, and, if so, (2) how to minimize damage to sleeping areas from logging. Macaques slept only in Atlas cedars (Cedrus atlantica). Consistent with predictions, macaques preferred sleeping in sheltered topography and dense vegetation, which may reduce exposure to wind, precipitation and cold, and preferred large trees that facilitate social huddling. This suggests that Barbary macaques employ strategic nocturnal microhabitat selection to reduce thermoregulatory costs and thus suitable sleeping areas may influence winter survival. To minimize negative impacts of logging on macaque sleeping areas, results suggest avoiding logging in topographical depressions and maintaining cedar densities greater than 250 ha-1 with average breast height greater than 60 cm. This study demonstrates how animal behaviour can be used to guide species-specific habitat management plans

Male breast cancer: a report of 127 cases at a Moroccan institution

Background: Male breast cancer (MBC) is a rare disease representing less than 1% of all malignancies in men and only 1% of all incident breast cancers. Our study details clinico-pathological features, treatments and prognostic factors in a large Moroccan cohort. Findings: One hundred and twenty-seven patients were collected from 1985 to 2007 at the National Institute of Oncology in Rabat, Morocco. Median age was 62 years and median time for consultation 28 months. The main clinical complaint was a mass beneath the areola in 93, 5% of the cases. Most patients have an advanced disease. Ninety-one percent of tumors were ductal carcinomas. Management consisted especially of radical mastectomy; followed by adjuvant radiotherapy and hormonal therapy with or without chemotherapy. The median of follow-up was 30 months. The evolution has been characterized by local recurrence; in twenty two cases (17% of all patients). Metastasis occurred in 41 cases (32% of all patients). The site of metastasis was the bone in twenty cases; lung in twelve cases; liver in seven case; liver and skin in one case and pleura and skin in one case. Conclusion: Male breast cancer has many similarities to breast cancer in women, but there are distinct features that should be appreciated. Future research for better understanding of this disease at national or international level are needed to improve the management and prognosis of male patients

Incidence of Gastric Cancer in Marrakech and Casablanca, Morocco

Gastric cancer is the fifth most common cancer globally with over 70% of new cases occurring in developing countries. In Morocco, oncologists in Marrakech suspected higher frequency of gastric cancer compared to Casablanca, a city 150 kilometers away. This study calculated age-specific, sex-specific, and total incidence rates of gastric cancer in Marrakech and was compared to the Casablanca population-based cancer registry. Using medical records from Center Hospital University Mohammad VI and reports from 4 main private pathology laboratories in Marrakech, we identified 774 patients for the period 2008–2012. Comparison of rates showed higher age-specific incidence in Marrakech in nearly all age groups for both genders. A higher total incidence in Marrakech than in Casablanca was found with rates of 5.50 and 3.23 per 100,000, respectively. Incidence was significantly higher among males in Marrakech than males in Casablanca (7.19 and 3.91 per 100,000, resp.) and females in Marrakech compared to females in Casablanca (3.87 and 2.58 per 100,000, resp.). Future studies should address possible underestimation of gastric cancer in Marrakech, estimate incidence in other regions of Morocco, and investigate possible risk factors to explain the difference in rates

A coherent picture of water at extreme negative pressure.

International audienceLiquid water at atmospheric pressure can be supercooled to 41 C (ref. 1) and superheated to C302 C (ref. 2). Experiments involving fluid inclusions of water in quartz suggest that water is capable of sustaining pressures as low as 140 MPa before it breaks by cavitation3. Other techniques, for which cavitation occurs consistently at around 30MPa (ref. 4), produce results that cast doubt on this claim. Here we reproduce the fluid-inclusion experiment, performing repeated measurements on a single sample--a method used in meteorology5, bioprotection6 and protein crystallization7, but not yet in liquid water under large mechanical tension. The resulting cavitation statistics are characteristic of a thermally activated process, and both the free energy and the volume of the critical bubble are well described by classical nucleation theory when the surface tension is reduced by less than 10%, consistent with homogeneous cavitation. The line of density maxima of water at negative pressure is found to reach 922:8 kgm3 at around 300 K, which further constrains its contested phase diagram